1. Field of the Invention
Embodiments of the present invention relate to a semiconductor device formed by a plurality of semiconductor modules including, for example, a power device.
2. Discussion of the Background
A power conversion inverter device has been widely used as one of power conversion devices. For example, an electric motor is generally used as a driving source of, for example, an electric vehicle or a hybrid vehicle. An inverter device is generally used to control various types of motors. As the power conversion device, a semiconductor module is used in which a power device, such as an insulated gate bipolar transistor (IGBT) or a free-wheeling diode (FWD), is sealed in a predetermined shape with a mold resin material. A plurality of semiconductor modules are combined to form a power conversion device.
A module-type electric device block has been proposed which includes a mutual coupling means. In the module-type electric device block, when two module-type blocks, such as mold cases which surround an electric device, are arranged and connected to each other, the two mold cases are coupled in a hinge manner. When one of the two cases is pivoted to come into contact with the other case, a protruding end of a tongue-shaped portion which is provided in one case is fitted to the outer surface of the other case to couple the two mold cases (for example, see JP 62-86900 A) (“Patent Document 1”).
As another attachment method, an inverter device has been proposed in which six main switching elements, which are modules forming one arm of the inverter device, are prepared, are divided into three sets each having two main switching elements, and the main switching elements in each set are connected by a U-phase main circuit board, a V-phase main circuit board, and a W-phase main circuit board (for example, see JP 3430192 B1) (“Patent Document 2”).
As another attachment method, a semiconductor device has been proposed in which three semiconductor modules are mounted on the upper surface of a heat sink, a reinforcing beam is arranged on the upper surface of the semiconductor module, with a leaf spring which traverses each semiconductor module interposed therebetween, and screws are inserted from the upper side of the reinforcing beam into the heat sink through the leaf spring and the semiconductor module to fix the three semiconductor modules to the heat sink (for example, see JP 4129027 B1) (“Patent Document 3”).
A semiconductor device has been proposed in which three columns of semiconductor device units in which a semiconductor chip is sealed with a resin, each column having two semiconductor device units, are arranged on a cooler; bolt tightening units are provided at both ends of each semiconductor device unit in the row direction; a wiring substrate is arranged on the upper surfaces of each semiconductor device unit and each bolt fastening unit; and bolts are inserted into the cooler through the bolt tightening units from the upper side of the wiring substrate to fix the semiconductor device units to the cooler (for example, see WO 2011/083737 A) (“Patent Document 4”).
However, in the related art disclosed in Patent Document 1, two mold cases having the electric devices provided therein are coupled to each other by the mutual coupling means including the hinge portion and the tongue-shaped portion. However, in this case, there is an unsolved problem that it is difficult to connect the two mold cases, with a desired gap therebetween, considering, for example, cooling efficiency.
In the related art disclosed in Patent Document 2, three main elements for an upper arm and three main element for a lower arm, which form the inverter device, are individually screwed to the radiation fin, the individual main circuit boards are mounted on the upper surfaces of the corresponding main elements for an upper arm and the corresponding main elements for a lower arm, the terminal portions are fixed to each other by screws, and each main circuit board is connected to a power board by a connector. Therefore, in Patent Document 2, there is an unsolved problem that the arrangement position of each main circuit board is determined by the power board and it is difficult to set the distance between the main circuit boards, that is, the distance between the main element for an upper arm and the main element for a lower arm which are adjacent to each other to a desired value, considering, for example, cooling efficiency.
In the related art disclosed in Patent Document 3, three semiconductor module, the leaf spring for pressure, and the reinforcing beam are arranged on the heat sink and are fixed to the heat sink by bolts. Therefore, in Patent Document 3, there is an unsolved problem that it is difficult to set the distance between the semiconductor modules to a desired value, considering, for example, cooling efficiency.
In the related art disclosed in Patent Document 4, six semiconductor device units are interposed between the bolt fastening units, the wiring substrate covers the semiconductor device units and the bolt fastening units, and the bolts are inserted into the cooler through the bolt fastening units from the upper side of four corners of the wiring substrate to fix the semiconductor device units to the cooler. Therefore, in Patent Document 4, there is an unsolved problem that the arrangement of the six semiconductor device units is determined by the wiring substrate and it is difficult to set the distance between the semiconductor device units to a desired value, considering, for example, cooling efficiency.